"I like to use a free-range old-breed pig such as Berkshire or large black," says Hafner. "They have a much better flavour and the fat is soft and delicious. They also seem to make the best crackling. I ask for a female pig - their flavour is better. Order one at your local farmers' market or specialist butcher. Leave the pork in the fridge uncovered overnight - it helps to dry the skin, which makes good crackling. I like to cook pork gently and past well done so it falls off the bone. This requires some attention. Take the pork out of the oven and give the meat a prod - when it's ready it will yield; if it springs back return it to the oven for another 15 minutes. If you find that the crackling has not quite crackled enough, you can turn the heat up to 200C and give the pork one last blast - that should do it." Start this recipe a day ahead to dry the pork skin.
Note Ask your butcher to score the pork skin for you. Wild fennel can be found growing along creeks and rivers. Alternatively you can use 2 tbsp fennel seeds, ground.